1. Field of the Invention
This invention concerns a particular stuffing box structure which is especially adapted for use with cables in a bore hole. It is applicable to cables that are connected end to end and have a connector which is larger in diameter than the cables.
2. Description of the Prior Art
While a stuffing box structure, per se, is of course old and well known, a problem arose in a situation which involved making surveys down a bore hole with a transducer. The requirements included a signal/power cable to the surface, and it required a pack-off gland at the top of the well for the cable. Such a pack-off gland was especially required if the bore hole was pressurized. Furthermore, the cable to be employed required different construction for the sections at the bottom and top ends thereof. Consequently, a connector was required to join the two ends of these different cables. Such a connector would have a larger diameter than the cables which would be joined thereby, and consequently, a problem of how to maintain the pressure seal was encountered. An example of the basis for the problem, relates to the retorting of oil shale, wherein the bottom of a bore hole is very hot and consequently, it requires a high temperature cable, while the top portion may use a lower temperature (easier-to-handle) cable. In that arrangement the cables may be a different size, and they are connected together with a connector having a size different from either of the cables.
Consequently, it is an object of this invention to provide a stuffing box structure which permits the use of multiple types of cable with a larger sized connector which can pass into or out of a bore hole while maintaining the pressure conditions therein.
Heretofore, there has been issued a U.S. Pat. to W. G. Bradford No. 1,762,211 issued June 10, 1930. However, that patent merely discloses an arrangement for having a packing head that will act as a stripper on the cable holding a down hole tool. The arrangement permits release of the stripper portion as the tool reaches the surface. The release arrangement is in the structure which holds the stripper head. This merely provides for the ability to remove the tool from the hole as it reaches the surface structure that holds the stripper. It is done by releasing the stripper from the holder thereof, as the tool is removed.